Rotary forging is a processing method of local deformation, multiple accumulation and finally overall forming. It uses the upper die with cone to press the blank locally along the central bus and gradually form. It has the advantages of labor-saving, small impact and easy metal filling the die cavity. Rotary forging dies and blanks are often subjected to eccentric load, so they have high requirements for die performance, and the blanks should not have too large height diameter ratio.
The tooth shape of spiral bevel gear rotary forging die has poor stress conditions, and the precision of rotary forging parts is required to be high, so it is particularly required to have high hardness, toughness, fatigue resistance and high wear resistance. The motion trajectory of spiral bevel gear formed by swing head mainly includes circle, multi leaf rose line or spiral line, and the motion trajectory of multi leaf rose line is the best.
The earliest rotary rolling mill is mainly used to replace large forging equipment for ingot billet forging. It is a slick mill developed in the United States in 1906. The swing head of the mill rotates and the workpiece rotates without swing action. In 1928, the British improved the slick rolling mill and put forward the concept of rotary forging. The axial rolling mill designed by the British improved the slick rolling mill, which was patented. It was not until the 1960s that the swing rolling process entered the practical application stage. By 1967, the Polish people continued to improve the design of the rolling mill and designed the swing die rolling mill. The swing head of this cold forming rolling machine has the movement of revolution and up and down swing of the vertical plane.
The former Soviet Union and Germany successfully developed bevel gear warm rolling machine and axial die rolling machine in the late 1960s and early 1970s respectively. The motion modes of the two rolling mills are the same, which are cone die rotation + translation and workpiece rotation. In 1972, the former Soviet Union continued to develop a spherical motion press with cone die revolution + rotation and workpiece translation. At present, the most successful swing rolling mills designed and manufactured abroad and widely used in production include: axial rolling mill in the former Federal Republic of Germany, bevel gear rolling mill in the former Soviet Union and swing die rolling mill in the United States. These rotary rolling machines are applicable to cold, warm and hot rolling forming processes. The swing die mill in Poland and the track cold forming press in Switzerland are mostly used in the cold swing rolling process.